I have created a port for Obsidian: freebsd-ports/Makefile at main · freebsd/freebsd-ports · GitHub
It will not be available for installing via pkg install, though, because its license doesn’t allow redistribution. Leave a +1 in this thread: Consider allowing redistribution in the EULA
Since you’ll have to install it from Ports, see the comment at the top of Makefile for instructions on how to avoid compiling most of the dependencies by hand.